The inventive concepts described herein relate to semiconductor memories, and more particularly, to memory systems including nonvolatile memory and to methods of programming executed by memory systems including nonvolatile memory.
Semiconductor memory devices may be volatile or nonvolatile. Volatile semiconductor memory devices are generally characterized by the loss of contents stored in a power-off state, whereas nonvolatile semiconductor memory devices are generally characterized by the retention of contents stored even in a power-off state.
Flash memory is one example of a nonvolatile semiconductor memory device which has been widely adopted in electronics industries. Flash memory may be used to store large quantities of voice, image data and other data in information appliances such as a computer, a cellular phone, a PDA, a digital camera, a camcorder, a voice recorder, an MP3 player, a handheld PC, a game machine, a facsimile, a scanner, a printer, and the like.
In the meantime, in an effort to meet the continuing demand for highly integrated memory devices, research has focused on the development of nonvolatile memory devices (hereinafter, referred to as a three-dimensional (3D) nonvolatile memory devices) where memory cells are arranged in three-dimensions. Interference between word lines is a particular concern that must be addressed in the design of 3D nonvolatile memory devices. However, charge trap flash (CTF) memory cells are may be utilized to increase a cell size, which can mostly elevate word line interference. This may allow for multi-bit data to be programmed at a memory cell in a so-called one-shot program mode where multiple data bits are simultaneously programmed at the memory cell, as opposed to a shadow program mode where 1-bit data is programmed at a time at the memory cell.